Dialkyl iminyl thionophosphates



M. J. DIAMOND Filed Nov. 24, 1954 DIALKYI.. IMINYL THINOPHOSPHATES Q m om v n moo w Q v o o. E M TM m T T m w ww d n .V 3 .IR mi O l m M Y l Nwm 1 f (,xz m f m @C IN .(ll. fk M o wZOmUIz Z IPOZMJ m v Q n w m .v mN00 v w M u w, W n. 1 E f m, @I M N w l f I i.@lal S L C c w O StatesDIALKYL IMINYL THIONOPHOSPHATESl Martin J. Diamond, Berkeley, Calif.,assignor to California Spray-Chemical Corporation, Richmond, Callf.,

a corporation of Delaware Filed Nov. 24, 1954, Ser. No. 470,909

1 Claim. (Cl. 260-461) The residual valences on the phosphorus andcarbon atoms may be satisfied with conventional radicals and 'selectedto emphasize certain desirable physical and chemical characteristicsassociated with the projected application of the compound.

Illustrative of a class of the compounds of the invention which havebeen found to possess lunusual toxicant properties are the compounds ofthe general formula:

P-O-N=A l, Re S in which R1 and R2 may be alkoxy, alkylthio, oralkylamino radicals; A may be a carbocyclic radical linked to the N=through a nuclear carbon atom or a radical in which R3 is an organicradical and R4 may be an inorganic or organic radical. The organicradicals of R4 and/or R3 may be hydrogen, heterocyclic, aromatic,acyclic or alicyclic radicals. For the sake of consistency innomenclature, the radical with the Valence bonding through the nitrogenhas been designated as an iminyl radical and, accordingly, thesecompounds are to be classied Ias O-organo iminyl thionophosphates.

These unique compounds have been produced by a number of generalizedmethods of preparation which result in the formation of thecharacteristic O-iminyl radical. Fundamentally, they involve thecondensation of an oxime with a halothionophosphate which is postulatedin accordance with the following equation:

According to thevarations in method of preparation, Y

atent may be either hydrogen, in the case of the free oxime, or a metalsuch as an alkali metal, in the case of a metal oXiInate. The residualvalences on the carbon of the oxime and the phosphorus of thehalophosphate are not critical to the reaction and may be satisfied withradicals designed to emphasize the physical and chemical characteristicsdesired in the final product.

One of the specific methods of preparation involves the reaction of ametal salt of an oxime and, preferably, the sodium salt with ahalothionophosphate and separation of the resulting metal halide. Thisreaction is preferably conducted in the presence of an inert solventsuch as petroleum ether, benzene, toluene, cyclohexane, etc., for thepurpose of facilitating the separation of reaction products, and at areaction temperature between about 0 C. and 120 C. Reaction temperaturesbelow 0 C. result in lan impractical rate of reaction, whereastemperatures above about C. usually result in a gradually decreasedyield of desired compound by reason of apparent decomposition in thereaction product. Another method of preparation which has been foundadvantageous is the reaction of the free oxime with thehalothionophosphate in the presence of a hydrogen halide sequesteringagent such as pyridine. Again, this reaction may be conducted with orwithout the presence of an inert reaction solvent and, preferably, atreaction temperatures between about 0 C. and 100 C. Another method whichlikewise avoids the necessity of preparing the 0X- ime salt is thereaction of the free oxime with the halothionophosphate and itsequivalent in the presence of an acid-binding compound such as sodiumcarbonate. VThe reaction is preferably conducted in the presence of an.inert solvent, and proceeds at an optimum rate between about 50 C. to120 C. Additionally, the reaction is enhanced by the presence of acatalyst such as metallic copper and/or potassium bromide.

Generally, the choice of method of preparation will depend upon thenature of the reactants and composition of the desired reaction product.It has been found that the yields of reaction product will vary with themethod of preparation and reaction conditions employed. On the basis ofmultiple preparations of the O-iminyl phosphates and thionophosphates ofVarying composition, it has been noted that generally the optimum methodfor preparing the O-iminyl phosphates is the reaction of the free oximewith the halophosphate in the presence of pyridine as the hydrogenhalide sequestering agent, whereas optimum yields of the O-iminylthionophosphates are obtained from the metal oxim-ate reaction with thehalothionophosphate.

As an illustration of the various types of reactants which have beenapplied in accordance with one or more of the aforementioned synthesismethods to produce representative compounds of the class of O-organoiminyl phosphates and thionophosphates, the following examples arecited: diethylchlorophosphate, diethylchlorothionophosphate,dimethylchlorophosphate, tetramethyldiamidochlorophosphate;

and acetoxime, methyl n-propyl ketoxime, methyl cyclopropyl ketoxime,methyl i-butyl ketoxime, mesityl oXime, ethyl oximinoacetoacetate,pchloroacetophenone oXime, dl-camphor oxime, monochloroacetoxime,cyclopentanone oXime, cyclohexanone oxime, pinacolone oxime,dimethylglyoxime, acetaldoxime.

As a means of identification and evidence of the characteristic grouping\c=N-o-P/ J\ of the compounds of ythe invention, representativecompounds were subjected to infrared spectographic analysis. Thespectrograms reproduced as Figs. 1 and 2 were representative of two ofthe simple members of the class of O-organo iminyl phosphates andthionophosphates. Fig. 1 represents the infrared spectrogram of0,0diethyl-O propyliden-Z-iminyl phosphatek prepared in accordance withExample 1, and Fig. 2 represents the infrared spectrogratn of0,0-diethyl-O-propyliden-Z-iminyl thionophosphate as prepared inaccordance with Example 2. These infrared spectrograms were prepared ona standard infrared recording spectrophotometer designed for measuringand recording the infrared transmission of solids, liquids and gases andconsisting of a double infrared beam which scans the spectrum throughthe wave length range of 2.0 to microns, one part of the beam passingthrough the sample under study, the other passing through a compensatingcell. In the spectrograms of Figs. 1 and 2, lines A and A1 are therecord of the undiluted compounds employing a 0.03 mm. NaCl cell,whereas lines B and B1 are records obtained from the 2 percent solutionsthereof in carbon disulfide employing a 0.12 mm. cell.

It will be noted that the principal characteristic absorption bands forthese types of compounds are at 6.0a, indicative of the C=N bond; 7.8M,representing the P- O bond or 15-l-a, in the case of the P S bond; and9.9/1, representing the P-O-C bond. The remaining strong absorptionbands and peaks are definitive of the various elemental bonds associatedwith the organic residues of the iminyl and phosphate radicals and willvary in accordance therewith.

As an illustration of the various ramifications in composition of theclass of compounds of the invention and 95 g. of sodium salt ofacetoxime was suspended in 250 ml. of dry benzene. 170 g. ofdiethylchlorophosphate was added gradually with stirring while coo-lingwith a water bath at room temperature. After the addition of thediethylchlorophosphate was complete, the mixture was warmed to 75 C. andheld for 2 hours. The sodium chloride which was formed in the reactionproduct was removed by filtration and the solvent was distilled from thefiltrate at reduced pressure, leaving 160 g. of an oil identified as`0,0-diethyl-O-propyliden y2-iminyl phosphate. High vacuum distillationof this oil resulted in a clear, colorless product With a boiling pointof 78 C. to 81 C. at 9 103 mm. pressure. This boiling point was theliquid pot temperature taken in a molecular-type still distillationassembly. The 0,0diethyl-O-propyliden-2-iminyl phosphate possessed arefractive index nD=1.4370, and analyzed as follows:

'This compound Was found to be soluble in water, methyl alcohol, ethylalcohol and benzene, and consider-ably less soluble in petroleum etherand normal heptane.

Example 2 285 g. of the sodium salt of acetoxime was suspended in 750ml. of dry toluene. 555 g. of diethylchlorothionophosphate was addedgradually with stirring while cooling with a water bath at roomtemperature. After the addition of the diethylchlorothionophosphate wascomplete, the mixture Was warmed to C. and held for 3 hours. Thereaction mixture was Washed with water to remove the suspended sodiumchloride which was formed. The toluene solution was then dried withanhydrous sodium sulfate and the solvent removed by distillation atreduced pressure, retaining 615 Vg. of a dark oil. High vacuumdistillation resulted in the recovery of0,0-diethyl-O-propyliden-Z-iminyl thionophosphate as an orange oil witha boiling point taken from the liquid pot temperature in a molecularstill of 57 C. to 60 C. at 5x103 pressure. This compound possessed amelting point of 20 C. and a refractive index HD2() of 1.4770. The0,0-diethyl-O-propyliden-Z- iminyl thionophosphate was determined to besoluble in methyl alcohol, ethyl alcohol and benzene, insoluble inwater, yand sparingly soluble in petroleum ether and normal heptaneExample 3 220 g. of acetoxime vand 518 g. of diethylchlorophosphate weredissolved in 1500 ml. of dry benzene. 255 g. of dry pyridine was addedgradually and the mixture reuxed at 78 C. for 2 hours. The white, solidpyridine hydrochloride which was formed was removed by filtration andthe benzene was removed .by distillation at reduced pressure, leaving anoily residue. High .vacuum distillation of this oil resulted in therecovery of 0,0- diethyl-O-propyliden-Z-iminyl phosphate as in Example1.

Example 4 73 g. of acetoxime Was dissolved in 400 ml. of dry toluene andmixed with 70 g. of sodium carbonate and 2 g. of metallic copper. 185 g.of diethylchlorothionophosphate was added gradually with stirring andthe mixture was heated to C. and held for 3 hours. After cooling, themixture was washed with water, filtered and the toluene layer dried withanhydrous sodium sulfate. An oily product was obtained after removal ofthe toluene. High vacuum distillation of the loil residue resulted inthe isolation of 0,0diethy1-O propyliden-Z-iminyl thionophosphate as inExample 2.

Example'S 153 g. of the sodium salt of acetoxime was mixed with 1500 ml.of dry ether. 142 g. of dimethylchloro.- phosphate was added graduallywhile cooling with ya water bath at room temperature. After the`addition Vof the dimethylchlorophosphate was complete, the mixture wasreuxed at 35 C. for 30 minutes. The sodium chloride which was formed wasremoved by filtration. Removal of the ether by distillation resulted inthe recovery of 1516 g. of 0,0-dimethyl-O-propyliden72-iminyl phosphateas a clear, yellow oil.

Example 6 9.5 g. of the sodium salt of acetoxime was mixed with 150 ml.of dry toluene. 17 g. of tetramethyldiamidochlorophosphate was addedgradually and, after the addition was complete, the mixture was refluxedfor 3 hours at C. The sodium chloride formed was removed by filtration,and distillation of the filtrate at reduced pressure for removal, of thetoluene resulted in a yellow, oily product identiiied asN,N,N,Ntetramethyl diamido-O-propyliden-Z-iminyl phosphate.

Example 7 2.7 g. of the sodium salt of mesityl oxime was mixed with 30ml. of dry ether, followed by the additionof 3.4 g. ofdiethylchlorophosphate, Whichwas added gradually with stirring. Themixture was then held `at 33 C. for '1 hour and then filtered to removethe precipitated sodium chloride. Separation of the ether by.distillation resulted in a yellow oil identified as 0,0diethylO-(4methyl-Bfpentenyliden-Zfiminyl) phosphate.

Example 8 26 g. of the sodium salt of mesityl oxime in 250 ml. of drybenzene was reacted with 36 g. of diethylchlorothionophosphate accordingto the procedure of Example 2. The reaction mixture was maintained at 78C. for 4 hours. After removal of the sodium chloride and the benzenesolvent, 46 g. of an orange oil was obtained which was identified as0,0diethyl-0(4-methyl-3-pentenyliden-2-iminyl) thionophosphate.

Example 9 3.8 g. of the sodium salt of p-chloroacetophenone oxime wastreated with 3.4 g. of diethylchlorophosphate following the procedure ofExample 7. The resulting 0,0diethyl-O-[l-(lt-chlorophenyl)ethyliden-l-iminyl] phosphate was recoveredas a yellow oil.

Example 10 3.5 g. -of the sodium salt of isophorone oxime was reactedwith 3.4 g. of diethylchlorophosphate according to the procedure ofExample 7. The resulting 0,0diethyl-O-(3,5,5-trimethyl-Z-cyclohexen-1-iminy1) phosphate was separatedand recovered as a yellow, oily product.

Example 11 13.5 g. of the sodium salt of cyclohexanone oxirne wasreacted with 17.2 g. of diethylchlorophosphate according to theprocedure of Example 2. The resulting 0,0diethyl-O-cyclohexaniminylphosphate was separated and recovered as a brown, oily product.

Example 12 6.8 g. `of the sodium salt of pinacolone oxime was reactedwith 8.6 g. of diethylchlorophosphate according to the procedure ofExample 1. The reaction was maintained at 111 C. for 2 hours, and0,0diethylO(3,3-d methylbutyliden-Z-iminyl) phosphate was separated andrecovered as a green, oily compound.

Example 13 6 g. of acetaldoxirne was dissolved in 40 ml. of dry etherand 8 g. of dry pyridine. The solution was initially cooled to 10 C. 17g. of diethylchlorophosphate was added gradually, during which time thetemperature approached 20 C. The resulting pyridine hydrochloride wasremoved by filtration and the ether was stripped from the product bydistillation to separate 0,0diethy1 O-ethylideniminyl phosphate as anoily compound.

Example 14 6.9 g. of the monosodium salt of dimethylglyoxime was reactedwith 9.4 g. of diethylchlorothionophosphate according to the procedureof Example 1. 9 g. of 0,0- diethyl-O-(3-oximinobutyliden-2-iminyl)thionophosphate was separated and recovered as a brown, oily product.

Example 15 6 g. of the sodium salt of ethylnitrolic acid in 30 m1. ofbenzene was reacted with 8 g. of diethylchlorophosphate according to theprocedure of Example 1. The

6 resulting 0,0diethyl-O( l-nitroethyliden-l-iminyl) phosphate wasseparated and recovered as an oily product.

Example 16 8 g. of the disodium salt of dimethylglyoxime was reactedwith 18.5 g. of diethylchlorothionophosphate according to the procedureof Example 1. 14 g. of bis-(0,0diethyl)0,0(buty1iden-2,3diiminyl)dithionodiphosphate was separated and recovered as a brownl oilyproduct.

Example 17 16.5 g. of the sodium salt of ethyloximinoacetoacetate wasreacted with 17.2 g. of diethylchlorophosphate according to theprocedure of Example 1. After separation and recovery, 20 g. of0,0diethyl-O-(1-carbethoxypropyliden-Z-iminyl) phosphate was obtained asa red oil.

Example 18 In addition to the foregoing examples, the sodium salts ofthe following oximes were reacted with diethylchlorothionophosphateaccording to the procedure of Example 1 to obtain the correspondingiminyl thionophosphates: methyl n-propyl ketoxime; methyl isopropylketoxime; methyl cyclopropyl ketoxime; methyl isobutyl ketoxime;monochloroacetoxime; and cyclopentanone oxime.

Although the unusual properties of this novel class of compoundsidentilied by the characteristic grouping \o=N-o-r -l\ are adaptable toa variety of practical applications, their toxicant properties have beendetermined and the compounds have been found eifective for theproduction of insecticida] compositions.

Obviously, many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof, and therefore only such limitations should be imposedas are indicated in the appended claim.

I claim: An iminyl thionophosphate of the formula R1 Ra P-0-N=C/ Rz/J\R4 in which R1 and R2 are lower alkoxy radicals and R3 and R4 areradicals selected from the group consisting of hydrogen and acyclicradicals containing from 1 to 4 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS2,389,718 Davis NOV. 27, 1945 2,494,283 Cassaday et al. Jan. 10, 19502,816,128 Allen Dec. 10, 1957 OTHER REFERENCES Atherton et al.: Chem. &Industry (1955), pp. 1183-1185.

